A gas sensitive material, a preparation method thereof, a gas sensor and application thereof

Abstract

The application relates to the technical field of gas sensors, and discloses a gas-sensitive material, a preparation method and a gas sensor thereof, and application, the preparation method of the gas-sensitive material comprises the following steps: (1) mixing polyvinylpyrrolidone, polyacrylonitrile, MoS2 and N,N-dimethylformamide to obtain a spinning solution; (2) obtaining a nanofiber membrane through an electrostatic spinning method; (3) in-situ synthesizing SnO2 nanoparticles on the nanofiber membrane through a solvothermal method; and (4) performing pre-oxidation treatment on the nanofiber membrane loaded with SnO2, and then performing calcination. The gas-sensitive material prepared through the method combines SnO2 and MoS2 which have high recognition ability for gases, and also combines CNFs (carbon nanofiber) which have high conductivity, high aspect ratio, large specific surface area and high stability, and the gas-sensitive material well maintains the structure of the carbon nanofiber, so that the gas-sensitive material has high gas-sensitive performance for hydrogen, good selectivity and repeated stability.

Description

Technical Field

[0001] This invention relates to the field of gas sensor technology, specifically to a gas-sensitive material, its preparation method, and gas sensors and applications. Background Technology

[0002] Lithium-ion battery safety accidents are a primary problem and a fatal hidden danger in the development of large-scale energy storage technology. The safety of lithium-ion batteries for energy storage has become a bottleneck technical problem that urgently needs to be solved in the large-scale promotion and application of energy storage technology. Battery thermal runaway refers to the overheating phenomenon caused by an exothermic chain reaction within the battery, resulting in a rapid change in the rate of temperature rise. Accidents involving energy storage batteries under extreme conditions such as mechanical damage, electrical abuse, and thermal abuse ultimately manifest as thermal runaway.

[0003] Research has revealed that the thermal runaway process of LIBs is typically accompanied by numerous side reactions and the release of gases, primarily hydrogen, carbon dioxide, methane, carbon monoxide, and ethylene. As thermal runaway progresses, the concentrations of gases such as H2, CO2, CH4, C2H4, and CO increase significantly before the smoke emission stage. In particular, detecting H2 is more predictive than detecting other characteristic thermal runaway gases. This demonstrates that real-time gas sensor monitoring can provide early warning of battery failures.

[0004] In the field of gas sensors, semiconductor metal oxide nanosheets (MOS) have swept across various markets at an extremely rapid pace since their development due to their high specific surface area and specific crystal interface exposure, attracting widespread attention from countries around the world. However, gas sensors made of MOS suffer from drawbacks such as long response / recovery times, high operating temperatures, and poor selectivity, which cannot meet increasingly stringent performance requirements and severely limit the further application of semiconductor sensors. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of long response / recovery time, high operating temperature and poor selectivity of existing gas sensors, and to provide a gas-sensitive material, its preparation method and gas sensor, and its application.

[0006] To achieve the above objectives, the present invention provides a method for preparing a gas-sensitive material, the method comprising the following steps:

[0007] (1) Mix polyvinylpyrrolidone, polyacrylonitrile, MoS2 and N,N-dimethylformamide to obtain a spinning solution;

[0008] (2) Obtain a nanofiber membrane by electrospinning the spinning solution;

[0009] (3) SnO2 nanoparticles were synthesized in situ on the nanofiber membrane by a solvothermal method;

[0010] (4) The SnO2-loaded nanofiber membrane obtained in step (3) is pre-oxidized and then calcined.

[0011] Preferably, in step (1), the concentration of polyvinylpyrrolidone in the spinning solution is 10-40 g / L;

[0012] Preferably, in step (1), the concentration of polyacrylonitrile in the spinning solution is 60-80 g / L;

[0013] Preferably, in step (1), the concentration of MoS2 in the spinning solution is 0.3 to 0.8 mol / L.

[0014] Preferably, in step (2), the conditions for electrospinning include: a positive voltage of 15-20 kV, a negative voltage of -1-3 kV, a flow rate of 0.4-0.6 mL / h, a temperature of 50-70 °C, and a receiving distance of 10-14 cm.

[0015] Preferably, step (3) includes:

[0016] The tin salt is dissolved in an organic solvent to obtain a precursor solution;

[0017] The nanofiber membrane is acidified, then mixed with the precursor solution, and then kept at 120–180°C for 8–12 hours.

[0018] Preferably, the concentration of tin salt in the precursor solution is 0.5–2 mol / L;

[0019] Preferably, the tin salt is SnCl2·2H2O and / or SnCl4·5H2O.

[0020] Preferably, the organic solvent is selected from at least one of ethanol, ethylene glycol, and propanol.

[0021] Preferably, the acidification treatment is carried out using a mixed acid solution, wherein the mixed acid solution is obtained by mixing concentrated sulfuric acid and concentrated nitric acid.

[0022] Preferably, in step (4), the pre-oxidation conditions include: a temperature of 260–300°C and a time of 20–40 min.

[0023] Preferably, in step (4), the calcination is a two-stage calcination process, wherein the temperature of the first stage is 230-270℃ and the temperature of the second stage is 520-580℃;

[0024] Preferably, the heating rate in the first stage is 0.5–3 °C / min, and the holding time is 40–80 min;

[0025] Preferably, the heating rate in the second stage is 1–3 °C / min, and the holding time is 150–200 min.

[0026] A second aspect of the present invention provides a gas-sensitive material prepared by the method described above.

[0027] A third aspect of the present invention provides a gas sensor comprising a gas-sensitive material prepared by the method described above.

[0028] The fourth aspect of the present invention provides the application of the gas-sensitive material prepared by the method described above or the gas sensor described above in hydrogen detection.

[0029] The method provided by this invention prepares a SnO2 / MoS2 / CNFs gas-sensitive material. This material combines SnO2 and MoS2, which have high gas recognition capabilities, with CNFs (carbon nanofibers), which possess high electrical conductivity, high aspect ratio, large specific surface area, and high stability. Furthermore, the material retains the structure of the carbon nanofibers well. Therefore, this gas-sensitive material exhibits high gas-sensing performance, good selectivity, and repeatability for hydrogen. For example, a gas sensor made from this material shows a sensitivity of 54.8% for 5000 ppm H2 and 67.2% for 10000 ppm H2, indicating high sensitivity. This gas sensor can be tested at a relatively low operating temperature (120°C). The gas sensor demonstrates similar performance and small errors in repeated tests, indicating good repeatability. Attached Figure Description

[0030] Figure 1 These are scanning electron microscope images of the MoS2 / PVP / PAN nanofiber membrane and gas-sensitive material prepared in Example 1 of this invention;

[0031] Figure 2 The graph shows the resistance response test results of the gas sensor prepared in Example 1 of the present invention to 1000-10000 ppm H2 at 120°C.

[0032] Figure 3 The graph shows the sensitivity test results of the gas sensor prepared in Example 1 of the present invention for 1000-10000 ppm H2 at 120°C.

[0033] Figure 4 The graph shows the resistance response test results of the gas sensor prepared in Example 1 of the present invention under repeated testing at 120°C with 10,000 ppm H2. Detailed Implementation

[0034] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0035] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0036] In the field of sensors, although semiconductor metal oxide nanosheets (MOS) have high gas recognition capabilities, gas sensors made from a single MOS suffer from drawbacks such as long response / recovery times, high operating temperatures, and poor selectivity. Transition metal chalcogenides (TMDs) also exhibit high gas recognition capabilities, but gas sensors made from a single TMD similarly suffer from long response / recovery times, high operating temperatures, and poor selectivity. This invention has discovered that by combining two specific MOS and TMD materials, SnO2 and MoS2, using electrospinning technology, the synergistic effect of the two materials can significantly improve the sensitivity of the material to hydrogen.

[0037] In view of this, the present invention provides a method for preparing a gas-sensitive material, the method comprising the following steps:

[0038] (1) Polyvinylpyrrolidone (PVP), polyacrylonitrile (PAN), MoS2 and N,N-dimethylformamide (DMF) are mixed to obtain a spinning solution;

[0039] (2) Obtain a nanofiber membrane by electrospinning the spinning solution;

[0040] (3) SnO2 nanoparticles were synthesized in situ on the nanofiber membrane by a solvothermal method;

[0041] (4) The SnO2-loaded nanofiber membrane obtained in step (3) is pre-oxidized and then calcined to obtain SnO2 / MoS2 / CNFs gas-sensitive material.

[0042] The method provided by this invention first obtains a MoS2 / PVP / PAN nanofiber membrane through electrospinning, then composites SnO2, MoS2, and CNFs, and then synthesizes SnO2 nanoparticles in situ on the nanofiber membrane using a solvothermal method. Finally, it undergoes pre-oxidation and calcination treatment to prepare a SnO2 / MoS2 / CNFs gas-sensitive material. The SnO2 / MoS2 / CNFs gas-sensitive material retains the fiber structure well, and under the combined action of SnO2, MoS2, and CNFs, it exhibits high gas-sensing performance, good selectivity, and repeatability for hydrogen.

[0043] In a preferred embodiment, in step (1), the concentration of polyvinylpyrrolidone in the spinning solution is 10-40 g / L, more preferably 20-30 g / L. Specifically, it can be 20 g / L, 21 g / L, 22 g / L, 23 g / L, 24 g / L, 25 g / L, 26 g / L, 27 g / L, 28 g / L, 29 g / L or 30 g / L.

[0044] In a preferred embodiment, in step (1), the concentration of polyacrylonitrile in the spinning solution is 60-80 g / L, more preferably 70-80 g / L. Specifically, it can be 70 g / L, 71 g / L, 72 g / L, 73 g / L, 74 g / L, 75 g / L, 76 g / L, 77 g / L, 78 g / L, 79 g / L or 80 g / L.

[0045] In a preferred embodiment, in step (1), the concentration of MoS2 in the spinning solution is 0.3 to 0.8 mol / L, more preferably 0.4 to 0.6 mol / L. Specifically, it can be 0.4 mol / L, 0.45 mol / L, 0.47 mol / L, 0.5 mol / L, 0.52 mol / L, 0.55 mol / L or 0.6 mol / L.

[0046] In a more preferred embodiment, in step (1), the concentration of polyvinylpyrrolidone in the spinning solution is 20-30 g / L, the concentration of polyacrylonitrile is 70-80 g / L, and the concentration of MoS2 is 0.4-0.6 mol / L. By controlling the concentration of each substance in the spinning solution within the above range, the nanofiber membrane obtained by electrospinning has a more uniform fiber diameter and is free of beads.

[0047] In a specific implementation, in step (1), the MoS2 is a nanosheet that has been peeled off by liquid phase exfoliation, so that the MoS2 nanosheets in the spinning solution are not agglomerated and are easier to disperse.

[0048] In a preferred embodiment, the electrospinning conditions in step (2) include: a positive voltage of 15–20 kV, a negative voltage of -1–-3 kV, a flow rate of 0.4–0.6 mL / h, a temperature of 50–70 °C, and a receiving distance of 10–14 cm. Under these electrospinning conditions, the obtained nanofiber membrane has a smaller diameter and is more uniform. The receiving distance refers to the straight-line distance between the needle and the receiving plate.

[0049] In a specific implementation, step (3) includes:

[0050] The tin salt is dissolved in an organic solvent to obtain a precursor solution;

[0051] The nanofiber membrane is acidified, then mixed with the precursor solution, and then kept at 120–180°C for 8–12 hours.

[0052] In a preferred embodiment, the concentration of tin salt in the precursor solution is 0.5–2 mol / L, more preferably 0.5–1.8 mol / L, specifically, for example, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L, 1 mol / L, 1.5 mol / L, 1.7 mol / L or 1.8 mol / L.

[0053] In a preferred embodiment, the tin salt is SnCl2·2H2O and / or SnCl4·5H2O.

[0054] This invention does not limit the specific selection of the organic solvent, and it can be any organic solvent commonly used in the art. In a specific embodiment, the organic solvent is selected from at least one of ethanol, ethylene glycol, and propanol.

[0055] In a preferred embodiment, the acidification treatment is carried out using a mixed acid solution, wherein the mixed acid solution is obtained by mixing concentrated sulfuric acid and concentrated nitric acid. More preferably, the mixed acid solution is obtained by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 3:1.

[0056] This invention does not impose any particular limitation on the specific concentrations of concentrated nitric acid and concentrated sulfuric acid; they can be concentrated nitric acid and concentrated sulfuric acid of commonly used concentrations in the art. In one specific embodiment, the mass fraction of the concentrated nitric acid is 67-69%, and the concentration of the concentrated sulfuric acid is 18.4 mol / L.

[0057] In a preferred embodiment, in step (4), the pre-oxidation temperature is 260-300°C, specifically, for example, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C or 300°C.

[0058] In a preferred embodiment, the pre-oxidation time in step (4) is 20 to 40 minutes.

[0059] In a preferred embodiment, step (4) further includes, before pre-oxidation, washing the SnO2-loaded nanofiber membrane with water and ethanol, and then drying it.

[0060] In this invention, the calcination is carried out under an inert atmosphere, wherein the inert atmosphere may be an argon atmosphere.

[0061] In a preferred embodiment, in step (4), the calcination is a two-stage calcination process, wherein the temperature of the first stage is 230-270°C and the temperature of the second stage is 520-580°C. By adopting the above calcination process, the nanofiber membrane can be carbonized more uniformly, thereby increasing the conductivity of the material.

[0062] More preferably, the heating rate in the first stage is 0.5–3 °C / min, and the holding time is 40–80 min.

[0063] More preferably, the heating rate in the second stage is 1–3 °C / min, and the holding time is 150–200 min.

[0064] In a preferred embodiment, the calcination process includes: placing the pre-oxidized nanofiber membrane in a tube furnace, heating it to 230-270°C at a heating rate of 0.5-3°C / min, calcining for 40-80 min, and then heating it to 520-580°C at a heating rate of 1-3°C / min, calcining for 150-200 min.

[0065] The present invention also proposes a gas-sensitive material prepared by the method described above.

[0066] This invention also proposes a gas sensor comprising a gas-sensitive material prepared by the method described above. Since the gas sensor of this invention uses the aforementioned gas-sensitive material, it possesses at least all the beneficial effects brought about by the technical solution of the aforementioned gas-sensitive material, which will not be elaborated upon here.

[0067] The present invention does not limit the specific fabrication method and structure of the gas sensor, and can use conventional fabrication methods and structures in the art. In one specific embodiment, the fabrication method of the gas sensor includes the following steps:

[0068] A1. Mix the gas-sensitive material with water, then grind it to obtain a slurry;

[0069] A2. The slurry is coated onto the Au electrode to form an electrode film;

[0070] A3. Aging the electrode containing the electrode film at 50-70℃ for 45-55 hours.

[0071] The present invention also proposes the application of the gas-sensitive material prepared by the method described above or the gas sensor described above in hydrogen detection.

[0072] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available products.

[0073] Example 1

[0074] (1) Polyvinylpyrrolidone (PVP), polyacrylonitrile (PAN), MoS2 and N,N-dimethylformamide (DMF) are uniformly mixed to form a spinning solution; wherein, in the spinning solution, the concentration of PVP is 25 g / L, the concentration of PAN is 75 g / L and the concentration of MoS2 is 0.5 mol / L.

[0075] (2) Inject the spinning solution obtained in step (1) into a 10 mL syringe and electrospin for 24 hours to obtain a MoS2 / PVP / PAN nanofiber membrane; wherein the electrospinning parameters include: positive voltage of +20 kV, negative voltage of -2 kV, flow rate of 0.5 mL / h, needle size of 20 G, temperature of 60 ℃, and receiving distance of 12 cm.

[0076] (3) Mix concentrated nitric acid and concentrated sulfuric acid at a volume ratio of 3:1 to obtain a mixed acid solution. Acidify the MoS2 / PVP / PAN nanofiber membrane obtained in step (2) in the mixed acid solution for 30 min.

[0077] (4) Add the weighed SnCl2·2H2O to 25mL of ethanol solvent and stir until homogeneous to obtain a precursor solution with a concentration of 1mol / L.

[0078] (5) Transfer the precursor solution obtained in step (4) and the nanofiber membrane after acidification in step (3) to a stainless steel reactor with a 50 mL polytetrafluoroethylene liner. Place the stainless steel reactor in an oven and heat it to 150°C for 10 hours. Then cool it to room temperature and take it out to obtain the in-situ SnO2-loaded nanofiber membrane.

[0079] (6) The in-situ SnO2-loaded nanofiber membrane obtained in step (5) was washed with deionized water and ethanol, and dried in an oven at 60°C for 10 h. Then the dried nanofiber membrane was pre-oxidized in a muffle furnace at 280°C for 30 min.

[0080] (7) The pre-oxidized nanofiber membrane in step (6) is placed in a tube furnace under Ar atmosphere, heated to 250°C at a rate of 1°C / min, calcined for 60 min, and then heated to 550°C at a rate of 2°C / min, calcined for 180 min to obtain the gas-sensitive material, denoted as SnO2 / MoS2 / CNFs.

[0081] (8) Clean and dry the commercially available flat Au electrode (extended platinum wire) with deionized water and ethanol respectively. The electrode is equipped with a test electrode and a heating electrode. The electrode heating temperature can be controlled by adjusting the input current. The upper surface of the electrode is Au, which is the test end, and the lower surface is Ru, which is the heating end. The outer dimensions of the flat electrode are 1.5×1.5mm.

[0082] (9) Weigh a certain mass of SnO2 / MoS2 / CNFs into an agate mortar, add deionized water, the mass ratio of deionized water to gas-sensitive material is 1:1, and then grind quickly and forcefully until the powder is ground into a uniform paste.

[0083] (10) The slurry obtained in step (9) is evenly brushed onto the flat Au electrode after the treatment in step (8) to form an electrode film and completely cover the Au electrode;

[0084] (11) Place the electrode obtained in step (10) on the aging table and age it at 60°C for 48 hours to obtain the gas sensor.

[0085] Example 2

[0086] The method described in Example 1 was implemented, except that in step (4), the concentration of SnCl2·2H2O in the precursor solution was 1.8 mol / L.

[0087] Example 3

[0088] The method described in Example 1 was implemented, except that in step (4), the concentration of SnCl2·2H2O in the precursor solution was 0.5 mol / L.

[0089] Example 4

[0090] The method described in Example 1 is implemented, except that in step (5), the stainless steel reactor is placed in an oven and heated to 130°C.

[0091] Example 5

[0092] The method described in Example 1 is implemented, except that in step (5), the stainless steel reactor is placed in an oven and heated to 180°C.

[0093] Comparative Example 1

[0094] The method described in Example 1 was carried out, except that MoS2 nanosheets were not added in step (1) (that is, the gas-sensitive material obtained was SnO2 / CNFs).

[0095] Comparative Example 2

[0096] The method described in Example 1 was carried out, except that SnCl2·2H2O was not added in step (4) (that is, the gas-sensitive material obtained was MoS2 / CNFs).

[0097] Test Example 1

[0098] The MoS2 / PVP / PAN nanofiber membrane and SnO2 / MoS2 / CNFs gas-sensitive material prepared in Example 1 were tested using a scanning electron microscope (SEM). The SEM used was a JEOL IT-800 field emission scanning electron microscope from Nippon Electron Ltd. The test results are as follows: Figure 1 As shown. Figure 1 In the image, (ab) are scanning electron microscope (SEM) images of MoS2 / PVP / PAN nanofiber membranes at different magnifications, (c) is a scanning electron microscope (SEM) image of SnO2 / MoS2 / CNFs gas-sensitive material, and (d) is a scanning electron microscope (SEM) image of pure SnO2 nanoparticles on SnO2 / MoS2 / CNFs gas-sensitive material.

[0099] Figure 1 The results (ab) show that the spun fibers are uniform and smooth, with a diameter of about 170 nm. Figure 1 (c) The in-situ loaded SnO2 carbon nanofibers, even after calcination, still exhibit an interwoven three-dimensional network structure. After being loaded with SnO2 nanoparticles, the carbon nanofibers have a rough and porous surface, significantly increasing the specific surface area and active sites of the gas-sensitive material, which is beneficial to its gas adsorption performance. Figure 1 (d) It can be seen that the SnO2 nanoparticles are uniform in size.

[0100] Test Example 2

[0101] In this test example, the sensitivity S of the gas sensor in the sensitivity test is defined as follows: Δ R / Ra, where Ra is the initial resistance of the gas sensor in argon, Rg is the resistance value of the gas sensor in the gas to be measured, and ΔR is the difference between the resistance of the gas sensor in argon and the resistance in the gas to be measured, |Rg-Ra|.

[0102] Gas sensing performance testing: The testing equipment used was the CGS-8 intelligent gas-sensitive analysis system and the DGD-V digital dynamic gas distribution system produced by Beijing Zhongju High-Tech Technology Co., Ltd.

[0103] 1. Sensitivity Test

[0104] (1) The sensitivity of the gas sensor prepared in Example 1 was tested under different hydrogen concentrations (1000-10000 ppm). The operating temperature of the gas sensor was 120℃. The test results are as follows: Figure 2-3 As shown.

[0105] Figure 2-3 The results show that the sensitivity increases with increasing H2 concentration. As the concentration increases, the sensitivity curve gradually flattens out, but it is still rising, indicating that the gas sensor has the characteristics of large range and high precision. The gas sensor exhibits sensitivities of 26.3%, 31.5%, 37%, 41.1%, 45.3%, 47.8%, 50.6%, 53.1%, 54.8%, 56.6%, 58.4%, 60%, 61.2%, 62.5%, 63.5%, 64.7%, 65.7%, 66.6%, and 67.2% for H2 gas at concentrations of 1000 ppm, 1500 ppm, 2000 ppm, 2500 ppm, 3000 ppm, 3500 ppm, 4000 ppm, 4500 ppm, 5000 ppm, 5500 ppm, 6000 ppm, 6500 ppm, 7000 ppm, 7500 ppm, 8000 ppm, 8500 ppm, 9000 ppm, 9500 ppm, and 10000 ppm, respectively.

[0106] (2) The sensitivity of the gas sensors prepared in Examples 2-5 and Comparative Examples 1-2 under different hydrogen concentrations was tested. The operating temperature of the gas sensors was 120℃. The test results are shown in Table 1 below.

[0107] Table 1

[0108]

[0109]

[0110] As can be seen from Table 1, the present invention improves the sensitivity of the gas sensor by combining SnO2 and MoS2.

[0111] (3) Repeat the test of the resistance response of the gas sensor prepared in Example 1 to 10,000 ppm H2 gas, wherein the temperature of the gas sensor is 120°C, and the test results are as follows. Figure 4 As shown.

[0112] Depend on Figure 4 It can be seen that the performance of the gas sensor remained almost unchanged after 17 consecutive repeated gas-sensing tests, proving that the gas sensor has good stability.

[0113] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a gas-sensitive material, characterized in that, The method includes the following steps: (1) Mix polyvinylpyrrolidone, polyacrylonitrile, MoS2 and N,N-dimethylformamide to obtain a spinning solution; (2) Obtain a nanofiber membrane by electrospinning the spinning solution; (3) Dissolve the tin salt in an organic solvent to obtain a precursor solution; acidify the nanofiber membrane and then mix it with the precursor solution, and then keep it at 120~180℃ for 8~12h. (4) The SnO2-loaded nanofiber membrane obtained in step (3) is subjected to pre-oxidation treatment and then calcined; In step (4), the calcination is a two-stage calcination process, wherein the temperature of the first stage is 230~270℃ and the temperature of the second stage is 520~580℃.

2. The method according to claim 1, characterized in that, In step (1), the concentration of polyvinylpyrrolidone in the spinning solution is 10~40g / L.

3. The method according to claim 1, characterized in that, In step (1), the concentration of polyacrylonitrile in the spinning solution is 60~80g / L.

4. The method according to claim 1, characterized in that, In step (1), the concentration of MoS2 in the spinning solution is 0.3~0.8 mol / L.

5. The method according to claim 1, characterized in that, In step (2), the conditions for electrospinning include: positive voltage of 15~20kV, negative voltage of -1~-3kV, flow rate of 0.4~0.6mL / h, temperature of 50~70℃, and receiving distance of 10~14cm.

6. The method according to claim 1, characterized in that, The concentration of tin salt in the precursor solution is 0.5~2 mol / L.

7. The method according to claim 1, characterized in that, The tin salt is SnCl2•2H2O and / or SnCl4•5H2O.

8. The method according to claim 1, characterized in that, The organic solvent is selected from at least one of ethanol, ethylene glycol and propanol.

9. The method according to claim 1, characterized in that, The acidification treatment is carried out using a mixed acid solution, wherein the mixed acid solution is obtained by mixing concentrated sulfuric acid and concentrated nitric acid.

10. The method according to claim 1, characterized in that, In step (4), the pre-oxidation conditions include: a temperature of 260~300℃ and a time of 20~40min.

11. The method according to claim 1, characterized in that, The heating rate in the first stage is 0.5~3℃ / min, and the holding time is 40~80min.

12. The method according to claim 1, characterized in that, The heating rate in the second stage is 1~3℃ / min, and the holding time is 150~200min.

13. A gas-sensitive material prepared by the method according to any one of claims 1-12.

14. A gas sensor, characterized in that, The gas sensor comprises a gas-sensitive material prepared by the method described in any one of claims 1-12.

15. The application of the gas-sensitive material prepared by the method of any one of claims 1-12 or the gas sensor of claim 14 in hydrogen detection.

Images